Diagnosis of everything from cancer to heart disease to mental illness would be covered. Family doctors will have to pass on dates of birth, postcodes and NHS numbers.

Officials insisted the personal information would be made anonymous and deleted after analysis.

But Ross Anderson, professor of security engineering at Cambridge University, said: 'Under these proposals, medical confidentiality is, in effect, dead and there is currently nobody standing in the way.' Nick Pickles, of the privacy group Big Brother Watch, said NHS managers would now be in charge of our most confidential information.

He added: 'It is unbelievable how little the public is being told about what is going on, while GPs are being strong-armed into handing over details about their patients and to not make a fuss.

'Not only have the public not been told what is going on, none of us has been asked to give our permission for this to happen.'

But last month, in the first sign of a dramatic shift away from this position, Health Secretary Jeremy Hunt said he wanted millions of private medical records to be stored and shared between hospitals, GPs, care homes and even local councils. He sold the programme as part of plans for a 'paperless NHS' by 2018 and claimed 'thousands of lives' would be saved.

But details of the changes have raised serious concerns among civil liberties and privacy campaigners, as well as health professionals

Last night GPs' leaders said the latest proposals were too broad.

'Patients must be given the option to opt out of any scheme that seeks to transfer identifiable information about them from their records to another source,' said a BMA spokesman.

'This opt-out should be widely advertised and explained in order that patients are reassured and understand the process being carried out.'

Phil Booth of the campaign group NO2ID said an unprecedented volume of data would be 'sucked up'.

'People have to trust in the notion of medical confidentiality. They expect to be able to talk in confidence to their GP,' he said.

'They don't expect their private conversations to be uploaded on to a national database where they will be made available for any number of purposes for the benefit of persons unknown.'

A spokesman for the NHS said last night: 'The NHS constitution makes clear what information can be used for by the NHS and this proposal complies exactly with that.'